753
FXUS63 KILX 082251
AFDILX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LINCOLN IL
551 PM CDT SAT AUG 8 2026
KEY MESSAGES
- TYPICAL SUMMERTIME HEAT AND HUMIDITY WILL RETURN TO CENTRAL
ILLINOIS EARLY NEXT WEEK. HEAT INDEX READINGS WILL PEAK AT OR
ABOVE 100 DEGREES ACROSS ALL OR PARTS OF THE AREA SUNDAY
THROUGH TUESDAY.
- CLUSTERS OF THUNDERSTORMS WILL TRACK ACROSS THE MIDWEST OVER
THE NEXT SEVERAL DAYS. THE PRIMARY FOCUS FOR STRONG TO SEVERE
STORMS WILL REMAIN NORTH OF THE I-74 CORRIDOR THROUGH MONDAY.
AFTER THAT, THE SEVERE WEATHER RISK MAY INCREASE ACROSS MUCH
OF CENTRAL ILLINOIS TUESDAY INTO WEDNESDAY.
DISCUSSION
ISSUED AT 230 PM CDT SAT AUG 8 2026
W/NW UPPER FLOW AROUND A DEEP LOW CENTERED NEAR HUDSON BAY HAS
PUSHED A WEAK COLD FRONT INTO CENTRAL ILLINOIS TODAY. 18Z/1PM
ANALYSIS SUGGESTS THE BOUNDARY HAS DROPPED JUST SOUTH OF THE
I-72 CORRIDOR WHERE THE CU-FIELD HAS BECOME MOST ROBUST. WITH
DEWPOINTS IN THE LOWER TO MIDDLE 70S AND MLCAPES OF AROUND
2500J/KG, WOULD NOT BE SURPRISED TO SEE ISOLATED CONVECTION
DEVELOP ALONG THE FRONT AS IT SINKS TOWARD I-70 OVER THE NEXT
FEW HOURS. HAVE INCLUDED 20 POPS ALONG/SOUTH OF A DANVILLE TO
TAYLORVILLE LINE ACCORDINGLY.
THE FRONT WILL STALL ALONG OR JUST NORTH OF I-64 TONIGHT, WITH
THE TRAILING END OF THE BOUNDARY ACTING AS THE FOCUS FOR RENEWED
CONVECTIVE DEVELOPMENT LATER TONIGHT. WHILE THE STRONGEST
SHORT-WAVE TROUGHS EMBEDDED WITHIN THE NW FLOW REGIME ARE WELL
TO THE NORTH ACROSS SASKATCHEWAN AND ONTARIO, A WEAKER WAVE IS
NOTED ON WATER VAPOR IMAGERY OVER WESTERN NEBRASKA. AS A 40-45KT
NOCTURNAL 850MB JET STREAK STRENGTHENS FROM THE TEXAS PANHANDLE
TO EASTERN SOUTH DAKOTA, CLUSTERS OF THUNDERSTORMS WILL FORM
AHEAD OF THE APPROACHING SHORT-WAVES. THESE STORMS WILL THEN
TRACK E/SE ALONG THE PREVAILING BAROCLINIC ZONE INTO PORTIONS OF
CENTRAL ILLINOIS ON SUNDAY. THE LATEST MODELS ARE A BIT SLOWER
WITH THIS PROCESS, KEEPING THE KILX CWA DRY THROUGH TONIGHT. THE
12Z CAMS CONTINUE TO EXHIBIT A HIGH AMOUNT OF VARIABILITY
CONCERNING THE TRACK AND EXACT AREAL COVERAGE OF CONVECTION ON
SUNDAY:HOWEVER, THE CONSENSUS STRONGLY SUGGESTS THE BULK OF THE
STORMS WILL TRACK ACROSS EASTERN IOWA INTO NORTHERN ILLINOIS
MOSTLY NORTH OF THE KILX CWA. WHILE A FEW GUSTY STORMS MAY GRAZE
THE NORTHERN COUNTIES ALONG/NORTH OF A MACOMB TO BLOOMINGTON
LINE DURING THE MORNING, WE WILL ALSO NEED TO KEEP AN EYE ON
ADDITIONAL CELLS FORMING ALONG THE PREVAILING OUTFLOW BOUNDARY
DURING THE AFTERNOON. WITH DEWPOINTS RISING BACK INTO THE MIDDLE
70S, SBCAPES WILL EXCEED 3500J/KG BY PEAK HEATING. WHILE THE
STRONGEST WINDS ALOFT WILL REMAIN TO THE NORTH ACROSS THE GREAT
LAKES, 0-6KM BULK SHEAR WILL INCREASE TO 30-40KT ACROSS CENTRAL
ILLINOIS. AS A RESULT, ANY CELLS THAT FORM ALONG THE OUTFLOW
WILL HAVE VIGOROUS UPDRAFTS AND MAY BE CAPABLE OF PRODUCING
STRONG/DAMAGING WIND GUSTS AND PERHAPS MARGINALLY SEVERE HAIL.
THE LATEST DAY 2 CONVECTIVE OUTLOOK CONTINUES TO HIGHLIGHT MUCH
OF THE AREA WITH A MARGINAL RISK (5-15% CHANCE) FOR SEVERE
WEATHER, BUT HAS NUDGED THE SLIGHT RISK (15-30% CHANCE)
SOUTHWARD TO THE I-74 CORRIDOR. HAVE THEREFORE UPDATED THE
SUNDAY AFTERNOON POPS TO BRING 20-40% STORM CHANCES AS FAR
SOUTH AS I-70. ASIDE FROM THE SCATTERED STORMS, SUNDAY WILL BE A
WARMER AND MARKEDLY MORE HUMID DAY AS HIGH TEMPERATURES CLIMB
INTO THE UPPER 80S AND LOWER 90S AND HEAT INDEX READINGS REACH
100 DEGREES.
ADDITIONAL NOCTURNAL STORM CLUSTERS WILL DEVELOP AND TRACK ALONG
THE PERSISTENT FRONTAL BOUNDARY SUNDAY NIGHT, MONDAY NIGHT, AND
TUESDAY NIGHT. THE MAJORITY OF THE STORMS AND THEREFORE THE
GREATEST RISK FOR SEVERE WEATHER WILL REMAIN ALONG/NORTH OF THE
I-74 CORRIDOR UNTIL PERHAPS TUESDAY NIGHT INTO WEDNESDAY AS
MODELS SHOW THE FRONT SINKING SOUTHWARD INTO CENTRAL ILLINOIS.
GIVEN THE CONTINUOUS STORM TRACK NEAR OR JUST SLIGHTLY NORTH OF
THE KILX CWA OVER THE NEXT FEW DAYS, THE EXACT EXTENT OF THE
BUILDING HEAT/HUMIDITY REMAINS TO BE SEEN. WHILE AIR
TEMPERATURES WILL REACH THE UPPER 80S/LOWER 90S AND DEWPOINTS
WILL CLIMB WELL INTO THE 70S, HEAT ADVISORY CRITERIA MAY
STRUGGLE TO BE REACHED ACROSS PORTIONS OF THE AREA. IN ADDITION,
THE HEAT WILL BE MITIGATED BY A S/SW BREEZE OF 10-15MPH SUNDAY
THROUGH TUESDAY. GIVEN THE UNCERTAINTY WITH THE EXACT TRACK OF
THE EXPECTED CONVECTIVE CLUSTERS AND THE POSITIONING OF ANY
RESIDUAL OUTFLOW, HAVE OPTED NOT TO ISSUE ANY HEAT HEADLINES AT
THIS TIME. THINK FUTURE SHIFTS WILL LIKELY GO WITH A HEAT
ADVISORY AT LEAST ACROSS PARTS OF THE CWA...MOST LIKELY SOUTH OF
I-74 FOR MONDAY AND TUESDAY.
AFTER THE TUESDAY NIGHT/WEDNESDAY STORMS, TEMPERATURES WILL COOL
INTO THE UPPER 70S AND LOWER 80S BY THURSDAY/FRIDAY. DESPITE THE
COOLING TREND, CENTRAL ILLINOIS WILL REMAIN CLOSE ENOUGH TO THE
BOUNDARY TO KEEP RAIN CHANCES ALIVE RIGHT THROUGH THE END OF
THE WEEK.
AVIATION /00Z TAFS THROUGH 00Z MONDAY/
ISSUED AT 550 PM CDT SAT AUG 8 2026
LIGHT WINDS TONIGHT WILL FIRM FROM THE SOUTH AROUND 10 KT AFTER
DAYBREAK, THEN GUST 20-25 KT SUNDAY AFTERNOON. WHILE THERE IS A
LOW CHANCE OF TSRA LATE SUNDAY MORNING AND AFTERNOON,
CONFIDENCE IN TIMING AND PLACEMENT IS TOO LOW TO MENTION IN
TAFS AT THIS TIME. ASIDE FROM THAT POSSIBILITY, VFR CONDITIONS
WILL DOMINATE. PATCHY MVFR FOG COULD AFFECT KCMI EARLY SUNDAY
MORNING.
ILX WATCHES/WARNINGS/ADVISORIES
NONE.
KEY MESSAGES...BARNES
DISCUSSION...BARNES
AVIATION...25
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